U.S. patent number 7,907,041 [Application Number 12/444,913] was granted by the patent office on 2011-03-15 for cladding element with an integrated reception unit for the contactless transfer of electrical energy and method for the production thereof.
This patent grant is currently assigned to ThyssenKrupp Transrapid GmbH. Invention is credited to Andreas Diekmann, Wolfgang Hahn, Qinghua Zheng.
United States Patent |
7,907,041 |
Hahn , et al. |
March 15, 2011 |
Cladding element with an integrated reception unit for the
contactless transfer of electrical energy and method for the
production thereof
Abstract
A cladding (cover) element (32) includes a reception unit which
is integrated therein. The reception unit contains a receiving coil
(10) for the contactless transfer of electric energy and a
plurality of flux-conducting elements (15a, 15b; 16a, 16b) that are
associated with the receiving coil (10) for concentrating the field
strength. The cover element (32) is made of a fiber-reinforced
plastic. The flux-conducting elements (15a, 15b; 16a, 16b) and the
receiving coil (10) are arranged in a base body (18) that is used
to position the elements and coil and are embedded with the base
body (18) in the cladding element (32). A process is also provided
for producing the cladding element (32).
Inventors: |
Hahn; Wolfgang (Kassel,
DE), Zheng; Qinghua (Taufkirchen, DE),
Diekmann; Andreas (Muchen, DE) |
Assignee: |
ThyssenKrupp Transrapid GmbH
(Kassel, DE)
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Family
ID: |
39092321 |
Appl.
No.: |
12/444,913 |
Filed: |
September 5, 2007 |
PCT
Filed: |
September 05, 2007 |
PCT No.: |
PCT/DE2007/001576 |
371(c)(1),(2),(4) Date: |
April 09, 2009 |
PCT
Pub. No.: |
WO2008/043327 |
PCT
Pub. Date: |
April 17, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100097168 A1 |
Apr 22, 2010 |
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Foreign Application Priority Data
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Oct 11, 2006 [DE] |
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10 2006 048 831 |
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Current U.S.
Class: |
336/90; 336/115;
336/117; 336/119 |
Current CPC
Class: |
B60L
13/03 (20130101); B60L 2200/26 (20130101); Y10T
29/49073 (20150115) |
Current International
Class: |
H01F
21/06 (20060101); H01F 27/02 (20060101) |
Field of
Search: |
;336/96,92,90 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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WO 2005/090112 |
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Sep 2005 |
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DE |
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102004056439 |
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Oct 2005 |
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DE |
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0 549 110 |
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Jun 1993 |
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EP |
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58 135619 |
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Aug 1983 |
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JP |
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03 178505 |
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Aug 1991 |
|
JP |
|
Primary Examiner: Mai; Anh T
Attorney, Agent or Firm: McGlew & Tuttle, P.C. McGlew;
John James
Claims
The invention claimed is:
1. A cover element comprising: a cover element portion; a receiving
unit integrated in said cover element portion; a receiver coil for
the physical contactless continuous transmission of electric power
between the receiving unit and a sending unit with relative
movement between the receiving unit and the sending unit, the
receiver coil being contained in said receiving unit; and a
plurality of flux-conducting elements associated with the receiver
coil and intended to concentrate a field intensity, and which are
formed of a material having high permeability compared to that of
air wherein: the cover element portion is manufactured from a
fiber-reinforced plastic; the receiving unit comprises a
prefabricated basic body for positioning the flux-conducting
elements and the receiver coil to establish the position of the
flux-conducting elements and the receiver coil relative to each
other and relative to the cover element portion; and the receiving
unit as a whole is embedded in the fiber-reinforced plastic.
2. The cover element in accordance with claim 1, wherein the basic
body is provided with depressions receiving the flux-conducting
elements.
3. The cover element in accordance with claim 1, wherein the basic
body consists of plastic.
4. The cover element in accordance with claim 3, wherein the basic
body consists of a foam having damping action.
5. The cover element in accordance with claim 1, wherein the
flux-conducting elements consist of a contiguous shaped part, which
is integrated with the basic body into a completely prefabricated
assembly unit.
6. The cover element in accordance with claim 5, wherein the
flux-conducting elements of comprise a material containing
ferrite.
7. The cover element in accordance with claim 1, wherein the
flux-conducting elements and the receiver coil are arranged loosely
in a basic body.
8. The cover element in accordance with claim 7, wherein at least
the flux-conducting elements are prefixed with an adhesive.
9. The cover element in accordance with claim 1, wherein the basic
body is provided with stop and positioning means for positioning
the receiver coil.
10. A cover element, comprising: a cover element portion; a
receiving unit integrated in said cover element portion; a receiver
coil for the physical contactless transmission of electric power,
the receiver coil being contained in said receiving unit; and a
plurality of flux-conducting elements associated with the receiver
coil and intended to concentrate a field intensity, and which are
formed of a material having high permeability compared to that of
air wherein: the cover element portion is manufactured from a
fiber-reinforced plastic; the receiving unit comprises a
prefabricated basic body for positioning the flux-conducting
elements and the receiver coil; and the receiving unit as a whole
is embedded in the fiber-reinforced plastic wherein the receiver
coil has two longitudinal sections, which are arranged at spaced
locations from one another, and end windings connecting same.
11. The cover element in accordance with claim 10, wherein: the
basic body has a space to receive the receiver coil; webs are set
up to support the longitudinal sections of the receiver coil; and
the basic body contains depressions arranged laterally from the
flux-conducting elements for receiving the end windings.
12. A cover element comprising: a cover element portion; a
receiving unit integrated in said cover element portion; a receiver
coil for the contactless transmission of electric power, the
receiver coil being contained in said receiving unit; and a
plurality of flux-conducting elements associated with the receiver
coil and intended to concentrate a field intensity, and which are
formed of a material having high permeability compared to that of
air wherein: the cover element portion is manufactured from a
fiber-reinforced plastic; the receiving unit comprises a
prefabricated basic body for positioning the flux-conducting
elements and the receiver coil; the receiving unit as a whole is
embedded in the fiber-reinforced plastic; and the cover element
portion comprises an outer shell and an inner shell and the basic
body is arranged as a spacer between the outer shell and the inner
shell.
13. The cover element in accordance with claim 12, wherein the
outer shell and the inner shell are connected to one another only
in an edge section surrounding the receiving unit.
14. A process for manufacturing a cover element with a receiving
unit, which is integrated in same and which contains a receiver
coil for the contactless transmission of electric power and a
plurality of flux-conducting elements, which are associated with
the receiver coil, are intended to concentrate the field intensity
and consist of a material with a high permeability compared to that
of air, the process comprising the steps of: preparing a basic body
intended to receive and position the flux-conducting elements and
the receiver coil; arranging the flux-conducting elements and the
receiver coil in the basic body; and enveloping the receiving unit,
with fiber-reinforced plastic wherein the outer shell is
manufactured in a separate process step and is used as a mold, into
which the receiving unit is inserted and is then enveloped, in the
enveloping step with an inner shell firmly connected to the outer
shell.
15. The process in accordance with claim 14, wherein the outer and
inner shells are manufactured with the use of fiber mats
impregnated with curable plastic.
16. The process in accordance with claim 15, wherein the outer
and/or inner shells are manufactured by manual lamination.
17. The process in accordance with claim 15, wherein the outer
and/or inner shells are manufactured with the application of
pressure and/or vacuum.
18. The process in accordance with claim 15, wherein the outer
and/or inner shells are manufactured with the use of prepregs.
19. The process in accordance with claim 15, wherein the outer
and/or inner shells are manufactured with the use of fiber mats
possessing different properties.
20. The process in accordance with claim 14, wherein a tunable
capacitor block connected to the receiver coil into a resonant
circuit is additionally connected to the cover element.
21. The process in accordance with claim 14, wherein the
flux-conducting elements and the receiver coil are arranged loosely
in the basic body and then inserted with this into the outer
shell.
22. The process in accordance with claim 14, wherein: the basic
body is provided with depressions intended to receive the
flux-conducting elements; the flux-conducting elements are
manufactured by pouring a liquid mixture of a casting resin and a
powder consisting of a material having high permeability into the
depressions of the basic body; and the basic body is inserted into
the outer shell after an at least partial curing of the mixture and
after the receiver coil is mounted.
23. The process in accordance with claim 14, wherein the basic body
is provided with stop means used to position the receiver coil.
24. The process in accordance with claim 14, wherein the basic body
is made of a plastic, especially a foam.
25. The process in accordance with claim 14, wherein the
depressions are prepared by machining the basic body.
26. The process in accordance with claim 14, wherein the basic body
is manufactured in a mold designed as a negative mold of the basic
body by casting, foaming or pressing.
27. The process in accordance with claim 14, wherein the receiver
coil is inserted into the basic body before the mixture is poured
in.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a United States National Phase application of
International Application PCT/DE2007/001576 and claims the benefit
of priority under 35 U.S.C. .sctn.119 of German Patent Application
DE 10 2006 048 831.8 filed Oct. 11, 2006, the entire contents of
which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention pertains to a cover element with a receiving
unit, which is integrated in same and which contains a receiver
coil for the contactless transmission of electric power and a
plurality of flux-conducting elements, which are associated with
the receiving coil and are intended to concentrate the field
intensity, and which are formed of a material having high
permeability compared to that of air and further relates to a
process for manufacturing a cover element
BACKGROUND OF THE INVENTION
Cover elements (cladding elements) of this type are known
especially in magnetic levitation vehicles (DE 10 2004 056 439 A1).
The receiving unit having a receiver coil is used for the
contactless, inductive transmission of electric power from a track
to a vehicle. At least one primary conductor, which is connected to
a power source and is designed as a transmitting coil, is provided
for this purpose at the track and at least one secondary receiver
coil is provided at the vehicle. The receiving unit including the
contacting elements belonging to it in the form of plug-type
connectors or the like is mounted on a shell-like cover element,
which covers a magnetic back box on a side facing the track or is
integrated in same. Among other things, carrier magnets for the
magnetic levitation vehicle and the means needed for controlling
same, which can be operated with the electric power supplied by the
receiver coil, are accommodated in the magnetic back box, which is
connected via frame straps to an undercarriage or body of the
vehicle. An autonomous assembly unit for the "carrying" function is
thus obtained.
To improve the magnetic coupling between the primary conductor and
the receiver coil and to avoid eddy current losses, the receiver
coil is provided with means for concentrating the lines of magnetic
flux generated by the primary conductor on its side facing away
from the primary conductor. These means contain flux-conducting
elements in the form of strips and connection elements connecting
the ends thereof, which said connection elements are made of a
material with high permeability and high electric resistance,
preferably a ferrite, especially a soft ferrite. The strips and
connection elements are connected into a grid frame, which is to be
placed on the receiver coil, by bonding or according to another
method.
The manufacture of flux-conducting elements from a material such as
ferrite or the like is carried out by pressing and subsequent
sintering of a powder prepared from this material. The
flux-conducting elements obtained hereby are comparatively brittle,
mechanically delicate and poorly processable. In addition, the
joining of the flux-conducting elements into a grid frame is very
labor-intensive.
For the same reason, the usual fastening of the receiver coil and
of the flux-conducting elements to the cover element by screwing,
bonding or the like is not simple. In addition, there is a risk
that the flux-conducting elements will be destroyed or become
separated because of the mechanical vibrations and shocks occurring
during the operation of the magnetic levitation vehicle, which
makes undesired maintenance and repair work necessary.
SUMMARY OF THE INVENTION
Based on this, the basic technical object of the present invention
is to design the cover element of the class described in the
introduction such that its manufacture is simplified, the
flux-conducting elements are securely integrated in the cover
element and long service life is therefore attained even when they
consist of a brittle, easily breakable material.
The present invention offers the advantage that a receiving unit,
which comprises the basic body with the flux-conducting elements
and the receiver coil, is preferably completely embedded in the
cover element manufactured from a fiber-reinforced plastic.
Additional means for fastening the receiving unit at or in the
cover element are not therefore necessary. In addition, not only
are the flux-conducting elements positioned based on their
arrangement in the basic body, but they are also held securely and
protected against mechanical shocks. This is especially true when
the basic body is manufactured from a foam with damping action,
which is preferred.
The present invention will be explained in more detail below in
connection with the attached drawings on the basis of exemplary
embodiments. The various features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its uses, reference is made to the
accompanying drawings and descriptive matter in which preferred
embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a schematic view showing a partial section through a
usual magnetic levitation vehicle in the area of a track provided
with a long stator;
FIG. 2 is a schematic perspective and greatly enlarged view of a
part of a receiving unit;
FIG. 3 is a schematic view showing a cross section through the
receiving unit and the primary conductor according to FIG. 2;
FIG. 4 is a perspective view of a basic body according to the
present invention which can be used to manufacture the receiving
unit according to FIGS. 2 and 3;
FIG. 5 is a sectional view showing enlarged sections along line V-V
in FIG. 4;
FIG. 6 is a sectional view showing enlarged sections along line
VI-VI in FIG. 4;
FIG. 7 is a sectional view through the basic body corresponding to
FIG. 5 after mounting a receiver coil and inserting flux-conducting
element;
FIG. 8 is a schematic exploded perspective view showing the
formation of an assembly unit according to the present invention
that can be used in the manufacture of the receiving unit;
FIG. 9 shows a perspective view of an outer shell of a cover
element according to the present invention, which said outer shell
is intended for receiving the basic body according to FIGS. 7 and
8;
FIG. 10 is a cross sectional view approximately along line X-X in
FIG. 9 through a complete cover element according to the present
invention; and
FIG. 11 is a schematic view showing a device for manufacturing the
cover element according to the present invention according to FIG.
10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in particular, FIG. 1 schematically shows
a cross section through a magnetic levitation vehicle 1, which is
mounted in the usual manner in such a way that it is able to travel
on a track, which extends in the longitudinal direction of a line
and which contains carriers 2 manufactured from steel and/or
concrete and track panels 3 mounted thereon. The magnetic
levitation vehicle 1 is driven by means of a long-stator motor,
which has stator packages 4 that are fastened under the track panel
3 and follow each other in the longitudinal direction thereof. The
energizing field of the long-stator motor is generated by at least
one magnet array provided with carrier magnets, which has magnet
poles facing the grooves of the stator packages 4, which said
grooves are open downwardly in FIG. 1. Not only does the carrier
magnet 5 provide the energizing field, but it also assumes the
carrying and levitating function by maintaining a preset gap
between the carrier magnet 5 and the stator packages 4 during the
operation of the magnetic levitation vehicle 1. The magnet array
containing the carrier magnets 5 is otherwise accommodated in a
magnetic back box 6, which is fastened to the magnetic levitation
vehicle 1 via laterally arranged frame straps.
A primary conductor 7, which is designed as a transmitting coil,
preferably contains a line section 7a, 7b running back and forth
and preferably extends over the entire length of the track, is
provided along the track. The two line sections 7a, 7b are fastened
to the carrier 2, e.g., by means of a bracket 8 consisting of an
insulator. The primary conductor 7 is connected, in addition, to a
power source 9 of, e.g., 200 A, which is preferably a
high-frequency power source and is shown only schematically.
A receiving unit with a receiver coil 10 is mounted on the magnetic
levitation vehicle 1. This receiver coil 10 is preferably designed
such that it does not extend around the primary conductor 7 but is
located opposite same at a short distance only. The receiver coil
10 preferably comprises a plurality of parallel conductors, which
are arranged relative to the primary conductor 7 such that they are
passed through by the lines of magnetic flux generated by this
primary conductor 7 or the line sections 7a, 7b and the current of
approx. 200 A supplied by the primary conductor 7 can be uncoupled
at the terminal ends thereof, not shown. The two terminal ends, not
shown, of the receiver coil 10 are connected in the known manner,
e.g., with a voltage transformer, which is part of a usual power
supply unit, which supplies the magnetic levitation vehicle 1 with
the electric power necessary for its operation. It is clear that
corresponding primary conductors 7 are preferably installed on both
sides of the carrier 2 when the magnetic levitation vehicles 1 are
provided with carrier magnets 5 on both longitudinal sides and that
as many receiving units are provided in the longitudinal direction
of the magnetic levitation vehicles 1 as are necessary for the
operation of the magnetic levitation vehicles 1 or desirable for
reasons of redundancy.
The receiver coil 10 is preferably manufactured as a prefabricated
assembly unit together with the necessary contacting elements,
e.g., plug-type connectors, and mounted on the magnetic back box 6.
It is especially advantageous to accommodate the receiver coil 10
at or in a shell-like cover element 11, which is fastened to a rear
side of the magnetic back box 6, which said rear side faces the
primary conductor 7.
The receiver coil 10 is preferably designed in the manner of a
so-called layer winding. As is shown in FIG. 2, it contains a
plurality of layers located in one plane. The individual layers are
preferably made of a conductor with round or square cross section
and have essentially straight first and second longitudinal
sections 10a, 10b, which extend in parallel to one another and
along the magnet array, as well as end windings 10c, which connect
the ends thereof. The longitudinal sections 10a, 10b extend in
parallel to the line sections 7a, 7b of the primary conductor 7 and
are used to generate voltage. The first longitudinal sections 10a
are associated with line section 7a and the second longitudinal
sections 10b are associated with line section 7b of the primary
conductor 7 such that the line sections 7a, 7b are arranged
approximately in the middle of the layer part formed by the
associated longitudinal sections 10a, 10b, as is shown especially
in FIG. 3. By contrast, the conductors of the receiver coil 10
extend in the area of the end windings 10c essentially at right
angles to the line sections 7a and 7b, respectively.
To increase the magnetic coupling between the primary conductor 7
and the receiver coil 10 and to avoid eddy current losses, the
receiving unit has, furthermore, on the side of the receiver coil
10 facing away from the primary conductor 7, a means for
concentrating the field intensity generated by the primary
conductor 7, as it is schematically indicated by lines of magnetic
flux 14a, 14b in FIG. 3. This means contains flux-conducting
elements, which consist of a material with high permeability and
high electrical resistivity. An especially preferred material for
this purpose is ferrite, especially soft ferrite, which is,
however, comparatively brittle, mechanically delicate and therefore
poorly processable because it is manufactured from ferromagnetic
powders by pressing and subsequent sintering. The flux-conducting
elements are therefore composed of many, comparatively small strips
of material and connection elements, which are connected to one
another by bonding or according to other methods to form grid
frames.
A plurality of first material strips 15a, which are arranged
essentially at right angles to the line section 7a and in parallel
to the winding plane formed by the longitudinal sections 10a, are
provided, e.g., on a side of the receiver coil 10 facing away from
line section 7a in a construction likewise shown in FIGS. 2 and 3.
A plurality of second material strips 15b, which are preferably
located in the same plane as the first material strips 15a, are
provided in a corresponding arrangement on a side of the receiver
coil 10 facing away from line section 7b. Both material strips 15a,
15b have a length that is somewhat greater than the height of the
layer parts formed by the longitudinal sections 10a, 10b, without
overlapping with the ends facing each other. The individual
material strips 15a, 15b are arranged in a grid-like pattern and in
parallel to one another at preselected distances.
The ends of the first material strips 15a are connected to one
another by first connection elements 16a, which are arranged
essentially in parallel to line section 7a. The ends of the second
material strips 15b are correspondingly connected by second
connection elements 16b. Components designed in the manner of grid
frames are formed as a result.
Both the material strips 15a, 15b and the connection elements 16a
and 16b preferably consist of a ferrite. In addition, they are
arranged close behind the longitudinal sections 10a, 10b and are
arranged such that they bring about a concentration of the lines of
flux 14a and 14b generated by the line sections 7a, 7b, as this is
schematically indicated in FIG. 3. It is assumed in FIG. 3 that the
current flows through line section 7a momentarily in a direction
exiting from the drawing plane and it flows through line section a
7b momentarily in a direction entering the drawing plane. Because
of the high permeability of the material strips 15a, 15b, the lines
of flux 14a, 14b are closed directly behind the line sections 10a,
10b, as is schematically indicated by arrows, as a result of which
the magnetic coupling is greatly increased. Higher eddy current
losses are at the same time prevented from developing because the
material strips 15a, 15b and connection elements 16a, 16b
magnetically shield the parts of the magnetic back box 6 located
behind them because of their high permeability. Finally, the
connection elements 16a, 16b shall bring about an extensively
uniform distribution of the magnetic flux within the grid frame
structure. The length of the material strips 15a, 15b and of the
connection elements 16a, 16b is therefore preferably selected to be
such that the largest possible number of lines of flux 14a, 14b are
collected or concentrated.
The connection elements 16a, 16b are preferably fastened on the
sides of the material strips 15a, 15b facing the line sections 7a,
7b. This leads to the advantage that they come to lie essentially
in the same plane as the longitudinal sections 10a, 10b of the
receiver coil 10, as is shown especially in FIG. 3. As a result, no
additional space is required for them, especially if their
thickness, which is sufficient from a magnetic point of view, is
approximately equal to the thickness of the longitudinal sections
10a, 10b.
Receiving units of the type described are known from the document
DE 10 2004 056 439 A1 (and corresponding application publication US
2008236973), which is made into the subject of the present
disclosure by reference to avoid further repetitions.
To simplify the manufacture of the grid frame comprising the strips
15a, 15b and connection elements 16a, 16b, a basic body 18 (FIG. 4)
is used according to the present invention as a starting component,
which is provided with depressions in the form of grooves or the
like wherever the flux-conducting elements are to come to lie and
can therefore be considered to be an organizing auxiliary means.
Webs left in place between the depressions are designed such that
their surfaces can also be used, at least partially, as contact
surfaces for the receiver coil 10.
As is apparent from FIGS. 4 through 7, the basic body 18 is
manufactured in the exemplary embodiment from an originally
plane-parallel panel, which has, like the receiver coil 10, an
essentially rectangular outer contour and has accordingly two long
longitudinal sides 18a arranged in parallel to one another and two
short, likewise essentially parallel front sides 18b arranged at
right angles thereto. In addition, the basic body 18 is divided by
a middle web 19 extending in parallel to the longitudinal sides 18a
into two halves, which are essentially mirror-symmetrical in
relation to this.
To mount the strips 15a, 15b (FIG. 2), each half of the basic body
18 is provided, from its broad side that is the upper broad side in
FIGS. 4 through 7, with a plurality of first depressions 20, whose
lower limitations or bottoms are indicated by broken lines in FIGS.
5 and 7. The depressions 20 extend into a first plane 21 of the
basic body 18 and are arranged at right angles to the longitudinal
sides 18a and to the middle web 19, on the one hand, and in
parallel to one another, on the other hand. The number and size of
these depressions 20 correspond to the number and size of the
strips 15a and 15b to be mounted.
Webs 22 left in place between the depressions 20 are provided
according to FIGS. 5 and 6, at their ends adjoining the
longitudinal sides 18a and the middle web 19, with second
depressions 23, which likewise extend into the first plane 21 and
are thus connected to the first depressions 20.
In one exemplary embodiment, which is considered to be the best so
far and is shown in FIGS. 4 through 7, the height of the parts 22a
of the webs 22 (FIG. 5) that remain after the second depressions 23
have been formed and face the longitudinal sides 18a is reduced, so
that these parts reach only a second plane 24, which has a distance
that corresponds to the thickness of the strips 15a and 15b from
the first plane 21. Third depressions 25, which are used to mount
the longitudinal sections 10a, 10b of the receiver coil 10, are
formed as a result. Depressions 25 extend at right angles to the
longitudinal sides 18a of the basic body 18 from the second
depressions 23 to the steps 22b of the webs 22 and have a length in
the direction of extension that corresponds to the width of the
receiver coil 10 to be inserted, whose longitudinal sections 10a,
10b can be seen in FIG. 7.
The surfaces of parts 22c of the webs 22, whose height is reduced,
are located in a third plane 26 of the basic body 18. The surfaces
of an edge section 27 of the basic body 18, which extends all
around, as well as of the middle web 19 are also located in this
plane 16, which has a distance from the second plane 24 that
corresponds essentially to the thickness of the receiver coil
10.
The basic body 18 is provided with additional depressions 28 (FIG.
4) extending into the second plane 24 in an area each adjoining the
front sides 18b. The size of these depressions is selected to be
such that they can receive the end windings 10c (FIG. 2) of the
receiver coil 10. In addition, the height of the different layers
of the receiver coil 10 is selected to be such that after it has
been placed on the upper surfaces or bottoms of the depressions 25
and 28, it closes flush with the third plane 26, as is shown in
FIG. 7.
The receiving unit is advantageously manufactured in the manner
shown in FIG. 8 as follows:
The basic body 18 is first provided with the depressions 20, 23, 25
and 28 and webs 22 shown in FIGS. 4 through 6 by subjecting a
plane-parallel panel, e.g., to a machining process, especially
various milling steps. The depressions 25 and 28 then form a space
intended for receiving the receiver coil 10. This space is
dimensioned such that, on the one hand, the receiver coil 10 comes
into contact with step 22b with its inner contour 10d when it is
inserted into the basic body 18 (FIG. 7) and is hereby positioned
in the transverse direction of the basic body 18 and, on the other
hand, it abuts against the free ends of the middle web 19 and is
thus oriented in the longitudinal direction of the basic body 18.
This state is shown in the lowermost picture in FIG. 8. In other
words, steps 22b and the ends of the middle web 19 form stop and
positioning means for exactly positioning the receiver coil 10 in
the basic body 18.
The flux-conducting elements 15a, 15b and 16a, 16b are prepared in
another process step. They are prepared, e.g., by pressing and
subsequent sintering from a material such as ferrite, especially a
soft ferrite, and this preparation may also be carried out fully
independently from the manufacture of the cover element according
to the present invention. In particular, the material strips 15a,
15b are prepared, on the one hand, corresponding to FIG. 2 such
that they exactly fit into the first depressions 20, which are
visible in the right-hand part of FIG. 6. On the other hand, the
connection elements 16a, 16b are prepared such that they exactly
fit into the second depressions 23, which are visible in FIGS. 5
and 6. To avoid premature rupture of the connection elements 16a,
16b, individual pieces thereof are prepared, which have,
analogously to FIG. 2, such a length that they extend over a small
number of material strips 15a, 15b only (cf. FIG. 8) and are
essentially only as long as the material strips 15a, 15b. The
material strips 15a, 15b and connection elements 16a, 16b can
subsequently be connected, corresponding to FIG. 8, second picture
from the top, by means of a mounting adhesive or the like into a
grid frame, which fits exactly into the depressions 20 and 23 of
the basic body 18.
Regardless of whether the flux-conducting elements 15a, 15b and
16a, 16b are integrated into such a grid frame or not, they are now
inserted into the depressions 20, 23 of the basic body 18. As is
schematically shown in the left-hand part of FIG. 6, the material
strips 15a and 15b come to lie in a depression 20 each and fill
this out over the entire length. By contrast, the connection
elements 16a and 16b are arranged, as is shown in FIG. 7, in the
depressions 23 of the basic body 18, and they are in contact with
the ends of the material strips 15a, 15b. As in the case of the
grid frame, a connection of the connection elements 16a, 16b can be
established with the material strips 15a, 15b by means of a
mounting adhesive or the like in this case as well.
Subsequent to the insertion of the flux-conducting elements 15a,
15b, 16a, 16b, the receiver coil 10 is placed on the basic body 18,
as is shown in FIGS. 7 and 8 (lowermost picture) such that their
longitudinal sections 10a, 10b come to lie in the third depressions
25 and hence on the surfaces of the web parts 22a and their end
windings 10c in the depressions 28.
According to a first exemplary embodiment of the manufacturing
process according to the present invention, the receiving unit,
which comprises the basic body 18, the flux-conducting elements
15a, 15b and 16a, 16b as well as the receiver coil 10 and is still
joined together loosely, is now placed into an outer shell 30 (FIG.
9) of a cover element corresponding to the cover element 11 in FIG.
1, which said outer shell was prepared in advance and was
manufactured from a fiber-reinforced plastic. This outer shell 30
forms a component defining the outer contour of the cover element
in the exemplary embodiment and at the same time a mold for
manufacturing the complete cover element. The receiving unit
prepared in advance is now inserted into the outer shell 30
preferably such that the receiver coil 10 comes to lie on its
bottom 30a. The receiving unit is subsequently enveloped with a
fiber-reinforced plastic. An inner shell 31, which is shown in FIG.
10 and is firmly connected to the outer shell 30, is formed as a
result, while the receiving unit is arranged at the same time in a
sandwich-like pattern between the two shells 30, 31. On the whole,
a cover element 32, in which the receiving unit is integrated
captively and essentially also indestructibly, is thus
obtained.
The cover element 32 may contain additional components besides the
receiving unit. These include, e.g., a tunable capacitor block, not
shown, which is connected to the receiver coil 10, forms a resonant
circuit with this and is used to tune this resonant circuit to a
natural frequency of, e.g., 20 kHz, which corresponds to the
frequency of the current of the primary conductor 7 (FIG. 1). In
addition, additional components, which are useful or necessary for
the operation of the carrier magnets 5 (FIG. 1), may be
accommodated in a space 33 of the cover element 32. In addition,
the basic body 18 may be provided, which is not shown, with the
necessary connection contacts for the receiver coil 10, and
additional components may, of course, also be arranged on the basic
body 18.
A mold 34 (FIG. 11), whose cavity defines the outer contour of the
cover element 32 or of the outer shell 30, is used to manufacture
the cover element 32 in a second exemplary embodiment of the
present invention. At least one first fiber mat 35 is first
inserted, preferably in the dry state, into this mold 34 to prepare
the outer shell 30. The receiving unit prepared corresponding to
FIG. 8 is then placed on this fiber mat, after which at least one
second, preferably likewise dry fiber mat 36 is placed on this
receiving unit. The arrangement is preferably selected such that
the two fiber mats 35, 36 have edge sections 35a, 36a, which lie
one on top of another and extend all around, so that the receiving
unit is surrounded by the fiber mats 35, 36 on all sides.
The mold 34 is now lined on its top side with a film 37 or the
like, which covers and seals its cavity and is connected to a
vacuum pump, not shown, through a channel 38 extending into the
bottom of the cavity. The fiber mats 35, 36 and the basic body 18
with its components are hereby pressed tightly against the bottom
of the cavity and against one another and the edge sections 35a,
36a are brought together. A casting resin is then pressed into the
cavity through a gate 39, which likewise opens, e.g., at the bottom
of the mold, in order to impregnate the fiber mats 35, 36 with the
casting resin, as this is commonly practiced in the manufacture of
shaped parts from fiber-reinforced plastics.
The casting resin is then cured or allowed to cure, optionally at
elevated temperature, after which the film 37 is peeled off and the
finished cover element is removed from the mold 34. To facilitate
this operation, the mold 34 may have been previously coated with a
mold release agent and at least one insert part 40 (cf. FIG. 10),
which makes it possible to slightly raise the finished cover
element, may have been provided between the two fiber mats 35, 36.
The cover element removed from the mold 34 corresponds, in turn, to
the cover element 11 in FIG. 1.
One advantage of the process described is that the bottom of the
outer shell 30 is made comparatively thin and the receiver coil 10
can therefore be arranged very close to the primary conductor 7
(FIG. 1), which increases the efficiency of said coil. In addition,
analogously to a double-T beam, the basic body 18 forms the middle
web between the two shells 30 and 31 and as a result a spacing
element, which ensures high rigidity of the cover element.
The manufacture of the fiber-reinforced cover element 32 may
otherwise also be carried out by means of other processes commonly
used in the manufacture of fiber-reinforced and especially glass
fiber-reinforced plastic parts. Besides the manual lamination and
the vacuum injection described, for example, the injection molding
and pressing technique and especially the use of prepregs, i.e.,
mats already impregnated with hot-curing resins, which are
subjected to further processing by hot or cold pressing, are
suitable. Furthermore, it is possible to combine a plurality of
mats possessing different properties, e.g., to arrange Aramide
fiber mats for sufficiently securing joints, glass fiber mats for
high strength and nonwoven mats for obtaining a good optical
appearance one on top of another in layers in the process described
on the basis of FIGS. 10 and 11.
To simplify the manufacture of the receiving unit comprising the
basic body 18, the flux-conducting elements 15a, 15b and 16a, 16b
as well as the receiver coil 10, it is possible according to
another preferred embodiment of the present invention to
manufacture the flux-conducting elements 15a, 15b and 16a, 16b by a
casting operation. The receiver coil 10 is preferably placed for
this onto the finished basic body 18 preferably in the manner shown
in FIG. 8 (lowermost picture) without individual flux-conducting
elements 15a, 15b and 16a, 16b having been introduced before. The
receiver coil 10 is then in contact with the steps 22b (FIGS. 5 and
7) and with the ends of the middle web 19, while the depressions
20, 23 remain free.
A liquid mixture, which contains a curable casting resin and a
powder, which consists of a material having high permeability, is
prepared in another process step. A powder of ferrite, preferably a
soft ferrite, is used for this, in particular. This mixture may, of
course, also have been prepared already before the manufacture of
the basic body 18 and/or before the insertion of the receiver coil
10 into this.
The finished mixture, which preferably contains a multicomponent
casting resin provided with a curing agent, is now poured into the
depressions 23 left free by the receiver coil 10 by means of
pouring nozzles, not shown. As an alternative, a pouring spout,
which passes over the length of the depressions 23, may be used for
this as well. The casting resin penetrates during the casting
operation not only into the depressions 23, but also into the
depressions 20, which extend between these and are partly under the
receiver coil 10, and fills these completely. The basic body 18 is
thus used as a casting mold. The casting resin is prevented from
running out into the depressions 28 by raised webs 22a at the
lateral ends of the web rows.
The casting operation is concluded when the level of casting resin
has reached the third plane 26 (FIG. 7). As a result, the casting
resin can rise up to level 26 in the areas located between the
parts 22c of the webs 22, as this is indicated in FIG. 3 by a
broken line 41. However, this does not compromise the function of
the strips 15a, 15b as flux-conducting elements.
One advantage of the process described is that a shaped part of the
type of a grid form is formed, which contains the strips 15a, 15b
and connection elements 16a, 16b shown in FIGS. 2 and 3 with the
difference that these are manufactured in one piece and form a
one-piece, contiguous grid frame, which is arranged recessed in the
basic body 18. Special measures for connecting the strips 15a, 15b
and connection elements 16a, 16b are therefore unnecessary.
Furthermore, it is advantageous that the receiver coil 10 is also
already inserted into the basic body 18 and is firmly embedded in
same by the casting operation. The basic body 18, the receiver coil
10 and the flux-conducting elements 15a, 15b, 16a, 16b therefore
form a structural and receiving unit, which is completely
preassembled or can be completely preassembled and which is
embedded as a whole in the cover 11 (FIG. 1) of the magnetic back
box 6. Finally, it is also advantageous that the cast
flux-conducting elements have a higher ductility than the ferrite
elements used otherwise, which are manufactured as compression
moldings.
The basic body 18 is preferably manufactured from a plastic,
especially a foam, e.g., polyurethane with highly damping
properties. As an alternative to machining, it is possible,
besides, to manufacture the basic body 18 as a whole by casting,
foaming or pressing with the use of a corresponding die, in which
case the depressions 25, 28 for the receiver coil 10 can be kept
free, e.g., by a correspondingly shaped displacement body.
The present invention is not limited to the exemplary embodiment
described, which can be varied in many different ways. This
applies, in particular, to the grid frame-like structure of the
flux-conducting elements shown in FIGS. 2 and 3, because these may
also be arranged in other advantageous patterns and can be made
larger or smaller than described. It may be advantageous, above all
in case of the use of the casting process described on the basis of
FIGS. 5 through 7, to design the flux-conducting elements 15a, 15b
(FIG. 2) as panels passing over the length of the receiver coil 10.
The webs 22 (FIGS. 5 through 7) could be eliminated altogether in
this case and the depressions 20 could be made continuous in the
longitudinal direction of the basic body 18. It would be possible
now, e.g., to fill in a first step the entire lower space of the
basic body 18 up to level 24 (FIG. 6) with the casting resin
mixture, then to insert the receiver coil 10 and finally to fill
the space occupied by the flux-conducting elements 16a and 16b in
FIG. 7 with the casting resin mixture. The shape of the cover
element 32 may be different as well, because this depends mainly on
whether it is to be provided with additional components or the like
or whether it is to cover such additional components. Furthermore,
it is clear that the receiver coil 10 is provided with connection
contacts, not shown, at suitable points and the depressions 28
(FIG. 4) may also be absent altogether, especially when it is
desirable to bend off the end windings 10c to the rear analogously
to DE 10 2004 056 439 A1. The cover element 32 would have to be
provided with correspondingly shaped side parts in this case.
Instead of flux-conducting elements made of ferrite, it would also
be possible to provide flux-conducting elements consisting of other
materials, e.g., soft iron, especially when the power transmission
takes place at such low frequencies that the losses generated
thereby are tolerable. Finally, it is obvious that the various
features can also be used in combinations other than those
described and shown.
While specific embodiments of the invention have been shown and
described in detail to illustrate the application of the principles
of the invention, it will be understood that the invention may be
embodied otherwise without departing from such principles.
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